net: ethernet: mtk_eth_soc: Fix DIM support for MT7628/88

When updating to latest mainline for some testing on the GARDENA smart
gateway based on the MT7628, I noticed that ethernet does not work any
more. Commit e9229ffd

 ("net: ethernet: mtk_eth_soc: implement
dynamic interrupt moderation") introduced this problem, as it missed the
RX_DIM & TX_DIM configuration for this SoC variant. This patch fixes
this by calling mtk_dim_rx() & mtk_dim_tx() in this case as well.

Signed-off-by: Stefan Roese <sr@denx.de>
Fixes: e9229ffd

 ("net: ethernet: mtk_eth_soc: implement dynamic interrupt moderation")
Cc: Felix Fietkau <nbd@nbd.name>
Cc: John Crispin <john@phrozen.org>
Cc: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Cc: Reto Schneider <code@reto-schneider.ch>
Cc: Reto Schneider <reto.schneider@husqvarnagroup.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>